Hmmm, well these details don't sound that positive to me and if I source that gameport-midi cable and won't be working properly, I won't have anyone else to pass it on, due to extremely low demand :/ I 'll look into further details but I am leaning towards to the usb-midi solution after your words. Will revert in next weeks after I receive the RPi3, the Pi Hat and rest of cables about how it went :)